Check out 12 of the 311 things guys do that guarantee they won't be dating or having sex.

By Ellen Rakieten and Anne Coyle

Photo: Ryan Baehr

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Double Denim

This is a denim shirt or denim jacket worn with jeans, which gives the illusion that you're wearing a denim jumpsuit. We know you love them both, but you're going to have to choose one or the other. Sorry. And don't go thinking that you can get away with substituting a "chambray" shirt for a denim one, either. They're the same thing. Plus, we're pretty sure "chambray" is French Canadian for "douche."